I use Insect[0][1] as my calculator and it is great and does not have the odd choice of having case-insensitive identifiers plus does not require me to have Haskell installed. I would prefer if Insect was written in a compiled language but I am glad that it exists and JavaScript is really not a deal breaker for me as I need nodejs installed anyway (the same cannot be said for Haskell and this is going to be true for most people) plus you can get "compiled" single binaries for it from the release page[2] that you can put in `~/.local/bin` and not worry about it. I highly recommend trying it out. A bit slow to start but if your window manager supports hiding/showing bound windows through user defined shortcuts (like bspwm, awesomewm, i3, sway, herbstluft and most other tiling window managers) then you can just have it launch in the background on startup and you will have a convenient calculator just a few keystrokes away.

[0] https://insect.sh/?q=%3F

[1] https://github.com/sharkdp/insect

[2] https://github.com/sharkdp/insect/releases